Rotating milking platforms are well known and are generally a large platform which is rotated about a vertical axis and on which cows are supported and rotated from an entry to an exit location during time that they are being milked.
A problem exists however in relation to the means by which the platform is supported. A supporting beam usually below the platform provides a circular support path toward an outer periphery of the platform. A plurality of wheels are positioned at spaced apart locations around a track and support the track for relative movement over each respective wheel with each wheel being anchored with respect to a base (the ground or some footing arrangement)
Each wheel implicitly is aligned to track in a linear direction which is to say that its axle will be aligned with a radius from a centre of rotation of the platform while the track of the beam is circular. This then means that there is a turning component in any movement of the beam as it passes over a supporting wheel. This then causes implicitly a twisting side thrust on the wheel and its support. The problem then is that this will implicitly (and does in fact) cause considerable side forces against any wheel and with this the potential to cause considerable wear.
The use of liquid lubricants to reduce wear is not tolerable in a milking shed environment where all mechanical elements will be subject to inundation for washing on a regular basis so that if oil or grease is used this can then be transferred into waterways after washing or even contaminate milk.
A difficulty then has been to have and adequately support a wheel for this purpose with a perimeter surface that will allow relative transverse rubbing across its outer perimeter with minimal wear without external lubricants and to be able to have such a surface secured in a way that will enable side thrust to be resisted while at the same time being practical for this application.